Comment 7 for bug 1831566

I agree that it is wise to intersect cq_cpumask with online_cpumask in cq_cpulist_set(), and if cpuset_weight(cq_cpumask & online_cpumask) == 0 -- ignore cq_cpumask and stick with default behavior.

I don't think cpu offlining is problematic here. If CPU is offlined -- the IRQ (and queue) will be served by another online CPU. Yes, it will break IRQ affinity and make cq_cpumask setting pointless, but this is system administrator's problem. The parameter is only useful for fine tuning and some resource planning in advance is required. I don't think that this side effect is enough to motivate "unsafe" tag.